Compile-time replacement of default function argument expressions, enabling type-safe, zero-runtime-cost retrieval for displaying defaults in CLI help, configurations, and generated documentation.
A Kotlin compiler plugin that lets you retrieve function default argument values at compile time.
Kotlin allows defining default arguments for function parameters, but there is no standard way to access those values programmatically. For example, if you want to display default values in a CLI help message or a configuration framework, you would need to either duplicate the values or rely on reflection.
This plugin replaces defaultArgOf function calls with the actual default value expressions at compile time, providing a type-safe solution with zero runtime cost.
// build.gradle.kts
plugins {
id("me.tbsten.defaultargcapture") version "0.1.0-alpha03"
}
Simply applying the plugin automatically adds the runtime library dependency and configures the compiler plugin.
import me.tbsten.defaultargcapture.runtime.defaultArgOf
fun greet(name: String = "World") {
println("Hello, $name!")
}
fun main() {
defaultName = defaultArgOf<String>(funName = , argName = )
println()
}
inline fun <reified T> defaultArgOf(funName: String, argName: String): T
| Parameter | Description |
|---|---|
T | The type of the default value |
funName |
fun serve(port: Int = 8080, host: String = ) { }
{
defaultPort = defaultArgOf<>(funName = , argName = )
defaultHost = defaultArgOf<String>(funName = , argName = )
println()
println()
}
| Limitation | Note |
|---|---|
| Only functions in the same module can be referenced | Default values from other modules are not available in the IR |
funName requires a fully qualified name | Short names may cause ambiguity |
defaultArgOf<T>(funName = "f", argName = "x") in your codeMIT
| Fully qualified name of the target function |
argName | Name of the target parameter |
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